Vernonia amygdalina and Catha edulis leaves as cheap feed source and effect on growth performance of Somali goat at East Harargha, Ethiopia

Kedir Adem and Feki Misbah

Wolkite University, College of Agriculture and Natural Resource, Animal Science Department P O Box 07, Wolkite, Ethiopia
misbahfeki@gmail.com

Abstract

Feed shortage is the key limiting factor for small ruminant production in Ethiopia. This study was conducted at Haromaya University with the aim of evaluating the effect of dried Vernonia amygdalina leaf (DVAL) supplementation on feed intake, digestibility and growth performance of Somali goat fed Catha edulis leftover as a basal diet. The experiment was carried out using 24 yearling male goats with a mean initial body weight of 12.57± 0.59 kg (means ± SD). The experimental animals were grouped in to four blocks based on their initial weight and four treatments were randomly assigned to each goat within a block. The treatments were only Catha edulis leftover provision or control group (V0) and Catha edulis leftover ad – libitum supplemented with 200, 300 and 400 g DM/day DVAL for Va200, Va300 and Va400 respectively. Ninety and 7 days were allowed for feeding and digestibility trial respectively. The result of the present study for dry matter (DM), crude protein (CP), organic matter (OM), neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL) contents of DVAL and Catha edulis leftover were 925 & 890, 942 & 917, 110 & 223, 520 & 580, 360 & 370, 90 & 110 g/kg DM respectively. The DM intake for Catha edulis leftover decreases significantly (P > 0.001) from 407 – 236.6 g/kg DM across all treatments. Whereas, the total DM (507 – 636.6 g/kg DM) and CP (67.1 – 115.2 g/kg DM) intake increased significantly (P > 0.001) in all treatments for DVAL supplemented diet. Likewise, OM (467.4 – 593.7 g/kg DM), NDF (288 – 345 g/kg DM) and ADF (186.6 – 231.5 g/kg DM) intake showed significant improvement especially between V400 and VA0. The total DM intake in percent live body weight (2.8 – 2.9%) showed no variation in all treatment. The apparent CP digestibility (0.56 – 78) showed significant improvement as the level of DVAL diet increased. Moreover, DM digestibility showed significant variation for Va400 (0.76) > Va300 (0.63) = Va200 (0.61) > Va0 (0.56) and also OM (0.50 – 0.74) and NDF (0.50 – 0.78) digestibility showed significant improvement (P > 0.001) especially between Va0 and Va400. The average daily weight gain ranged from 21.7 – 58.5 g/day showing significant (P > 0.001) change for Va400 = Va300 > Va200 > Va0. And also feed conversion efficiency (4.3 – 9.2%) showed a significant (P > 0.001) increase along all treatments. Therefore, it can be concluded that increased level of DVAL meal resulted linear improvement in DM intake, growth performance and feed conversion rate leading to exploitation of these cheap feed source for small scale goat fattening.

Keywords: Chata edulis, digestibility, goat, supplementation, Vernonia amygdalina, weight gain

Introduction

Ethiopia is well known for its diverse and large livestock population in Africa being a home to about 33 million goat and 31 million sheep (CSA 2017). Goats (Capra hircus) are found across all agro-ecological zones and are suitable for very extensive to highly mechanized production systems (Wilson 1992). Goat breed are mainly kept by pastoral and small holder farmers for multiple purpose role in various part of Ethiopia.

Many studies agreed that insufficient and poor quality feed, particularly during the dry season, is one of the most important constraints to livestock feeding system in Ethiopian (Adunga et al 2000; Shapiro et al 2015). Although different reports showed some variation on the contribution, the major feed resources of the country indicated were natural pasture/green fodder (54.6%), crop residues (31.6%), hay (6.81%), industrial by products (1.53%) and very small amount of improved forages (0.31%), while non – conventional feeds accounted for about 5.11% (Adunga et al 2000; Shapiro et al 2015). Natural pasture and crop residue have shown remarkable seasonality in yield and quality and lack the critical nutrients that support animal growth particularly during dry season. Whereas, concentrates use is limited by cost, low supply and accessibility.

To progress this feed problem, initiating the use of indigenous non-conventional feed would be considered as an excellent option. Khat leftover is among non – conventional feed which have been widely used especially by resource poor household. Khat (Chata edulis) is a cash crop where its leftover is used by sheep and goats. Reported annual production of khat in 2019 was about 274,777 tons (CSA 2019). A few feeding trial showed that khat can be a good source of feed except its low CP content (Mohammed 2005; Yoseph 2007; Misganew et al 2012). So if its nutritive value can be improved through cheap protein source multipurpose tree like vernonia, khat leftover scattered everywhere can be changed from compound pollution to feed shortage solution.

Vernonia amygdalina, locally known as “Girawa”, is among multipurpose trees which rapidly grow and regenerate. It is drought tolerant plant and grows under a range of ecological zones in Africa and produces a larger mass of forage (Bonsi et al 1995). There are some studies that suggested different rate of Vernonia amygdalina supplementation to improve feed intake and growth performance of sheep and goat. Abegunde et al (2017), Fajemisin et al (2010) and Gezahegn et al (2020) suggested better intake and growth performance when Vernonia amygdalina leaf meal inclusion in concentrate diet not exceeding 10%, 50% and 75% respectively. However, Aynalem and Taye (2008) reported positive effect of Vernonia amygdalina supplementation on live weight gains of lambs and suggested for more research on higher level of inclusion. In addition to the different view on level of Vernonia amygdalina inclusion, there is also no study on the effect of Vernonia amygdalina supplementation on khat leftover. Therefore, this study was conducted with the objective of evaluating effects of different levels of dried Vernonia amygdalina leaf supplementation on feed intake, digestibility and growth parameters of Somali goats fed Catha edulis leftover as a basal diet.

Photo 1. Khat shopping		Photo 2. Khat waste material
Photo 3. Khat leftover dumped and burning around kat selling centers

Photo 4. Vernonia amygdalina grown around residential area

Materials and methods

Description of the study area

The experimental trial took place at Haramaya University, East Hararghe, Ethiopia (9^o20’N; 42^o03’E and an altitude of 1980 meter above sea level). It has a moderate average temperature of 16^oC with the mean maximum and minimum annual temperature range of 24.0^oC – 9.7^oC. The mean annual rainfall is 780 mm. Sorghum is the stable crop and Catha edulis is the primary cash crop. Small scale sheep and goat fattening is commonly practiced mostly feeding on Catha edulis leftover (Mishra et al 2004; CSA 2017).

Experimental animals and feed management

Twenty four male Somali goats with initial body weight of 12.57± 0.59 kg (means ± SD) were purchased from local markets at Babile. Age of the animals was estimated based on dentition and owners information. Experimental animals were subjected to quarantine for 21 days during which they were treated for internal parasite using broad spectrum anti-helmenthic (Albendazole) and dipped for external parasites using acaricides (diazinone 60%) and also vaccinated against anthrax and pasterollosis. Leftover of Catha edulis was purchased from the local market at Aweday town and the surrounding areas; whereas Vernonia amygdalina leaves were collected from the surroundings compound. Fresh leaves of Vernonia amygdalina and Catha edulis leftover were spread on plastic sheet and dried under shade, placed in plastic sacks and were stored for later use.

Experimental design and treatments

A randomized complete block design (RCBD) was used with four treatments. The experimental goats were blocked based on initial body weight into four blocks of six animals each. The initial body weight had been determined as a mean of two consecutive body weight measurements after overnight fasting. Animals within a block were then randomly assigned to treatments (control group - Va0, Va200, Va300 and Va400 g/d Vernonia amygdalina dried leaf supplementation) and were penned individually. The basal diet (Catha edulis leftover) was provided to allow for 20% refusal rate to ensure that every animal had ad-libtum access. Water and mineral licks were freely available to the animals all the time. Supplemental feed was provided twice a day at 8:00 and 16:00 h by dividing in to two equal haves.

Feed intake and body weight gain

The feeding trial lasted for 90 days following an adaptation period of 14 days to the diet and experimental condition. The amount of feed provided and refusal from each animal was recorded daily throughout the experimental period to determine daily feed intake of the animals as the difference between feed offered and refusal. Samples of feed offered per batch of feed had been taken and pooled and sub – sampled at the end of the experiment for chemical analysis. The refusal samples were pooled per treatment in to the four samples. The body weight of the goats were recorded at the beginning of the feeding trial and at every 10 d interval after overnight fasting to determine body weight change during the experimental period. Average daily body weight gain (ADG) was calculated as the difference between final and initial weight divided by the feeding days. Feed conversion efficiency (FCE) was determined by dividing ADG in gram by daily dry matter (DM) intake in gram.

Digestibility trial and chemical analysis

Digestibility was conducted at the end of the feeding trial and lasted for 10 days (3 d for adaptation to fecal bags and 7 d of fecal collection). Grab of samples from each feed and refusal from each animal was collected each day to make a weekly composite feed samples. The refusal samples were pooled per treatment. Fecal collection for digestibility measure had also been made and the daily fecal output was weighed and recorded for each animal. The fecal output of each animal was thoroughly mixed, and 20% of the feces voided were sampled to make a composite of fecal samples for each animal over the collection period. The fecal samples were stored frozen at negative 20⁰ C pending chemical analysis. Apparent digestibility coefficient of nutrients was calculated using the formula below (NRC 2007).

A sub-sample of feed offered, refusal feed and faces were analyzed for DM, ash and OM contents following the procedure of AOAC (1990). The nitrogen content was estimated according to the micro-Kjeldahl method (AOAC 1990) and CP was calculated as Nitrogen * 6.25. Organic matter content was calculated as 100 minus ash percentage. Neutral detergent fibers (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL) were determined based on the procedures of Van Soest and Robertson (1985).

Data analysis

The data obtained on feed intake, digestibility coefficient and weight gain were subjected to analysis of variance (ANOVA) using the SAS software package (SAS 2011). The difference between treatments means was separated by using least significant difference (LSD) test. The ANOVA model used for the data analysis was:

Y_ij = µ +T_i + B_j +E_ij

Where Y_ij = Response variable, µ = Overall mean, T_i = Treatment effect, B_j = Block effect and E _ij = Random error

Results and discussion

Chemical composition of the feed

Chemical analysis of feed samples is shown in Table 1. The CP content of dried Vernonia amygdalina leaf is doubles that of khat (Chata edulis) leftover. On the other hand the NDF, ADF and ADL values for the two diets appeared to be comparable. The slight decrease in CP content and increase in NDF, ADF and ADL values in the refusal of the basal diet as compared to the offered indicate selectivity of animals to khat leftover.

The CP content of dried Vernonia amygdalina leaf in the current study was similar to 221 – 225 g/kg DM (Fajemisin et al 2010; Gezahegn et al 2020). But, greater than 148 and 162.3 g/kg DM reported by Bonsi et al (1995) in Ethiopia and Okoli et al (2003) in South-eastern Nigeria respectively. And also, lower CP value than 240 – 244 g/kg DM reported by (Mekoya et al 2007; Aynalem and Taye 2008).

Neutral detergent fiber (NDF) and ADF content of Vernonia amygdalina leaf in the present study was similar to the report of Aynalem and Taye (2008) and Okoli et al (2003). But, higher value than Bonsi et al (1995) and lower value than Gezahegn et al (2020). The higher CP and fiber content of DVAL in the current analysis indicates that Vernonia amygdalina can be a cheap source of feed that can complement low protein and fiber content energy diet.

The CP and OM content of khat leftover used in this investigation was comparable with the values of 109 – 126 g/kg DM and about 900 g/kg DM respectively (Mohammed 2005; Yoseph 2007; Misganew et al 2012). Whereas, the NDF and ADF content of khat leftover were higher than the observation of (Mohammed 2005; Yoseph 2007; Misganew et al 2012)

The nutritional analysis of khat left over in this investigation showed greater CP content of grass hay (about 8% CP), comparable OM content (about 90%) to that of grass hay, but lower NDF (73 – 80%) and ADF (45 – 49%) than that of grass hay (Walie et al 2012; Tadesse et al 2016; Gezahegn et al 2020). This may show Chata edulis as promising non – conventional feed source and substitution of ever decreasing grass hay.

The variation in nutritive values of dried Vernonia amygdalina leaf and khat leftover observed in the current study might be attributed to the stage of growth, plant parts used, form of usage as well as differences in geographical locations (Bonsi et al 1995; McDonald et al 2002; Misganew et al 2012)

Dry matter and nutrient intake

Comparable to this work, Walie et al (2012) revealed khat leftover intake of 228 – 307 g/d DM at dried and fresh form. The same author showed, lower intake of total DM (535 g/d), OM (478 g/d), CP (53 g/d), NDF (323 g/d) and ADF (184 g/d) DM basis for Hararghe highland goats fed dried khat left over and grass hay as basal diet.

The DM and nutrient intake found in this study was within the range of Gezahegn et al (2020) study on replacement of nougseed cake with dried mulberry and vernonia mixed leaves’ meal at 25 to 100%. The study revealed 756 – 577 total DM, 698 – 577 OM, 107 – 88 CP, 350 – 288 NDF and 223 – 181 ADF g/d intake. A study on Tigray highland sheep fed ration containing different level of khat left over (Brhanu and Gebremariam 2019) showed similar CP intake of about 95.7 – 118 g/d while higher intake of NDF (380 – 497 g/d) and ADF (227 – 257 g/d). On the other hand, lower DM (385 – 415 g/d), CP (34 – 40 g/d) and NDF (240 – 256 g/d) intake was reported for West Africa Dwarf goat supplemented with leaf mixture of Vernonia amygdalina and Tithonia diversifolia as a direct replacement for brewers dried grains (Abegunde et al 2017). Total DM intake (2.8 – 2.9%) as percent body weight in this study was within the range of reported values for different breeds of tropical goats (Devendra and Burns 1983). Similarly, Matiwos (2007) reported 2.7 to 2.9% body weight DM intakes for Sidama goats fed hay and supplemented with cottonseed meal.

The total DM, CP, NDF and ADF intake increased with increasing of Vernonia amygdalina supplementation, whereas the basal diet intake showed a decreasing trend (Table 2.) This might be due to substitution of the basal diet by the supplement as well as increased level of CP source. Provenza (1995) noted that supplementation tends to have a positive effect on total DM intake but may have positive or negative effects on intake of the basal forage and often there is a substitution effect, where intake of the fibrous feed decreases to an extent that varies with the digestibility of the basal feed. Similar to this observation increased level of DM and nutrient intake were reported for small ruminants supplemented with graded levels of Vernonia amygdalina leaf meal and were fed hay and teff straw as basal diet (Bonsi et al 1995; Fajemisin et al 2010; Abegunde et al 2017)

Different studies on small ruminant feeding trial agreed that increased level of CP in a diet result higher DM intake. For example, Sukanten et al (1992) reported that goat fed grass as basal diet and supplemented with shrub and tree fodders containing higher CP consumed more forage. An increased in DM intake as the level of CP increased in the diet of goats was also stated (Negesse et al 2001). Similarly, Girma et al (1994) indicated sheep fed maize stover when supplemented with legumes showed significantly higher total DM intake. Cheek (2005) also revealed supplementation to be liable in increasing DM intake in lambs fed with oat hay and barley straw, which further resulted in increased CP intake.

Figure 1 illustrates the increasing trend in total DM intake of all experimental groups during the whole feeding period which might be related with increment in live body weight. McDonald et al (2002) stated that the nutrient requirement of growing animals changes throughout the growing period in direct response to the changing needs of the individual organs and systems making up the whole animals.

Dry matter and nutrients digestibility

Table 2 shows improvement in digestibility as level of Vernonia amygdalina supplements increased. Digestibility coefficient of CP increased (P > 0.01) in all treatment. Digestibility of DM also improved (P > 0.01) among VA400 > VA300 = VA200 > VA0.

The digestibility coefficient found in this experiment were comparable to Walie et al (2012) report for total DM (73%), OM (75%), CP (63%), NDF (67%) and ADF (56%) values. Whereas, higher than 44.8 % in vitro DM digestibility (Aynalem and Tesfaye 2008) and 48.8 – 54.6% NDF and 18.5 – 28.5% ADF percent digestibility (Brhanu and Gebremariam 2019). On the other hand, the rate of digestibility was lower than other studies on Vernonia amygdalina supplementation together with energy rich diet (Abegunde et al 2017; Gezahegn et al 2020).

The value of digestibility coefficient (Table 3) indicates there is a general trend of improvement in DM, OM, CP, NDF and ADF digestibility as Vernonia amaygdalina supplementation increases. Increased nutrient digestibility in supplemented treatments might be due to higher CP content, better rumen fermentation as well as anti-parasitic benefit of Vernonia amaygdalina.

In line with the current study, John (1994) reports that apparent digestibility of CP was influenced significantly with high inclusion rate of Vernonia amaygdalina leaf meal. Likewise, Athanasiadou et al (2005) stated favorable digestibility of DM and CP might be due to laxative, anti-helmithic potentials and beneficial effect of tannin and protein quality of Vernonia amaygdalina leaf meal. Supplementation of multipurpose legume tree was also described to increase protein supply to the host animal by increasing the supply of both degradable and undegradable protein, and by creating a favorable rumen environment resulting in enhanced fermentation of the basal roughage and thus increased microbial protein synthesis (ILRI 1995). Other studies also observed an increase in DM, OM and N digestibility with increasing level of browse legume and high protein diet fed to sheep and goats (Ash and Norton 1987; Lu and Michael 1990).

Many studies on feed trial agreed that good quality feed rich in protein promotes fiber digestibility resulting the overall increase in feed conversion. A potential increase in DM, OM, NDF and hemicellulose digestibility was indicated when legumes (like lucerne and Desmodium intratum) were fed at different levels with low quality basal diets. The reasons put forward for this improvement includes stimulated cellulolytic microbial growth, a reduction of retention time of digesta, increased nitrogen supply and rumen fermentation (Ndlovu and Buchanan-Smith 1985; Goodchild and Memeniman 1994; Adugna 1999).

Weight gain and FCE

There were linear improvements in feed DM intake, live weight gain and feed conversion rate, as the level of Vernonia in the diet was increased (Table 3 ; Figures 1 to 3). This might be due to presence of tannin and phenolic compound (generally referred as antinutrients) which reduce excessive rumen microbial degradation of protein, but resulting higher protein bypass and better utilization of amino acid and improved performance. Ezekiel et al (2015) indicated phenol and tannin content of 1.76mg/100g and 3.33mg/100g in Vernonia amygdalina leaves. On the other hand, Powers (1964) reported that several flavonoids including phenolic acids showed inhibitory activity toward bacteria studies. One of the beneficial effects of these compounds is plant-protein protection against excessive degradation leading to reduced soluble nitrogen (N) and better N use efficiency by animals. Now a day, people understood the concept and commercially preparing protein bypass feeds products for ruminant uses (Niderkorn and Jayanegara 2021).

Figure 1. Adding Vernonia foliage to the diet all goats lead to linear increases in play dry matter intake	Figure 2. Adding Vernonia foliage to the diet all goats lead to linear increases in live weight gain

Figure 3. Adding Vernonia foliage to the diet all goats lead to linear improvements I feed conversion

The average daily weight gain found in this study was within the range of 21 – 51 gram reported for small East African goats fed low and high level of concentrates (Hango et al 2007). Average daily weight gain of 34 – 95 g/day was also reported for Ethiopia sheep fed different level of vernonia (Aynalem and Taye 2008). Comparable to this outcome, Tadesse et al (2016) found ADG of 51.4, 42.1 and 41.3 g/day for Hararghe highland, Bati and Short – eared Somali goat breeds respectively fed concentrate diet. Similarly, Gezahegn et al (2020) mentioned ADG of 56 – 86 g/day for lambs supplemented with different level of dried mulberry and Vernonia mixed leaves’ meal. The live weight gain found in this trial was slightly higher than ADG of 38.4 – 33 g/day for WAD goats fed with 10% - 20% Tithonia diversifolia and Vernonia amygdalina leaf meal (Abegunde et al 2017) and ADG of 33 – 49 g/day for Hararghe Highland goat fed fresh and dried khat left over (Walie et al 2012).

However, ADG (21.7 – 58.5g/day) recorded in this study was lower than ADG reported for goats fed with balanced ration (Lu and Michael 1990; Salah et al 2014; Gezahegn et al 2020). Salah et al (2014) quantified about 100 gram of weight gain for about 7.90 – 8.97 MJ ME/Kg. Lu and Michael (1990) also indicated ADG of 115 g/day for diets containing 10.3 MJ/kg ME. Likewise, average daily gain of 104, 106 and 117 g/day was reported for Nubian goats fed balanced diets with 11.2, 12.7 and 15.1% CP, respectively (Lu and Michael 1990).

Feed conversion efficiency (FCE) in the current study was higher than 0.054 reported by Walie et al. (2012). While it is comparable to 0.08 – 0.11 mentioned for lambs fed 100% and 50% mulberry and Vernonia leaf mixed meal (Gezahegn et al 2020). Nonetheless, the FCE was much lower than 0.142 – 0.108 for three Ethiopian goat breed fed balanced diet (Tadesse et al 2016).

The present study was in agreement with Aynalem and Taye (2008) who concluded higher level (above 400 g/d) of Vernonia amygdalina supplementation for sheep fed grass hay as basal diet. Nevertheless, better weight gain was reported with smaller amount (about 100 g/d) Vernonia amygdalina supplemented for goat and sheep fed concentrate diet (Fajemisin et al 2010; Abegunde et al 2017; Gezahegn et al 2020). Therefore, supplementation of Catha edulis with Vernonia amygdalina plus high energy feed like maize might give a better weight gain. Yet, a detail chemical analysis and correlation of Vernonia leaf with fibrous and energy rich diet is needed.

Generally, no weight losses during the experimental period were observed, which indicate the basal diet satisfying maintenance requirements of the animals. Furthermore, goats fed only Catha edulis leftover exhibited ADG of 21.7 g/day which might indicate the quality of Catha edulis leaf. Consequently, Catha edulis leaves provided nutrients more than required for maintaining body weight throughout the experimental period. This is supported by the chemical analysis of feed samples that shows the CP contents of the basal diet was more than the recommended maintenance requirements for goats (Van Soest et al 1991).

Average daily gain in the present study was highly correlated with the dry matter and nutrient intakes. The tendency for higher daily live weight gains with increasing levels of Vernonia amygdalina leaf may be a function of higher total digestible DM, OM and CP intakes of goats which was in agreement with Owen and Zinn (1988) who after reviewing a large amount of body weight data concluded that added dietary protein resulted in increased rate of weight gain for over 85% of feeding trials. Van Soest et al (1991) demonstrated that live weight gain is impaired if the level of protein in a given diet is below 8%. Furthermore, Skerman and Riveros (1990) stated 7% CP content in DM as the threshold level for normal rumen function and ideal to maintain weight for sheep and goat.

Conclusion

The present study demonstrated that linear improvement in DM intake, live weight gain and feed conversion efficiency as the level of Vernonia amygdalina supplementation increasing in goat fed khat leftover. This might be due to protein bypass from ruminal microbial digestion as a result of tannin and phenolic compound resulting better metabolism and nutrient availability. But this needs a detail investigation.

Acknowledgments

The authors acknowledge the Ministry of Science and Higher Education of Ethiopia for funding this research. We also like to acknowledge the support of those friends during the implementation of the experiment and paper write up.

References

Abegunde Taye Olurotimi, Ajayi Festus Tope, Olona Joseph Folami and Balogun Fatima 2017 Supplemental value of leaf based concentrates with Panicum maximum hay on performance of West African dwarf goats. African Journal of Agricultural Research 2017; Vol. 12(9):723-729. https://doi.org/10.5897/AJAR2016.11263.

Adunga Tolera, Merkel R C, Goetsch AL, Sahlu T, Negesse T 2000 Nutritional constraints and future prospects for goat production in East Africa. In: Opportunities and challenges of enhancing goat production in East Africa. Conference held at Debub University, Awassa, Ethiopia, November 10–12, 2000, pp. 43–57

AOAC (Association of Official Analytical Chemists) 1990 Official methods of analysis, 15^th ed. Association of Official Analytical Chemists, Washington DC; 1990.

Ash A J and Norton WB 1987 Studies with the Australian Cashemer goat. II. Growth and digestion in male and female goats given pelleted diets varying in protein content and energy level. Australian Journal of Agricultural Research 1987; 38: 957-969.

Athanasiadou S, Tzamaloukas O, Kyriazakis I, Jackson F and Coop R L 2005 Testing for direct anthelminthic effects of bioactive forages against Trichostrongylus colubriformis in grazing sheep. Veterinary parasitology 2005; 127: 233 – 243.

Aynalem Haile and Taye Tolemariam 2008 The feed values of indigenous multipurpose trees for sheep in Ethiopia: The case of Vernonia amygdalina, Buddleja polystachya and Maesa lanceolata. Livestock research for rural development 2008; 20 (3); www.lrrd.org/lrrd15/9/okol159.htm.

Bonsi M L, Osuji PO, Tuah A K and Umunna N N 1995 Vernonia amygdalina as a supplement to teff straw (Eragrostis tef) fed to Ethiopian Menz sheep. Agroforestry System 1995; 31(3):229-241. https://doi.org/10.1007/BF00712076

Brhanu A and Gebremariam T 2019 Using khat (Catha edulis) leftover meal as feed for sheep: its implication on feed intake, digestibility and growth. Online Journal of Animal and Feed Research. 2019; 9(5): 191 – 197; https://dx.doi.org/10.36380/scil.2019.ojafr27.

Cheek P R 2005 Applied animal nutrition: feed and feeding 2005 3^rd ed. Oregon State University. ©2005 Pearson; 2005

CSA (Central Statistical Agency) 2017 Agricultural sample survey 2016/17. Volume II report on livestock and livestock characteristics of private peasant holdings. Federal Democratic Republic of Ethiopia, Central Statistical Agency (CSA), Addis Ababa, Ethiopia. Statistical bulletin 2017.

CSA (Central Statistical Agency) 2019 Agricultural sample survey 2018/19. Volume I. Report on Area and production of major crops for private peasant holdings. The federal democratic republic of Ethiopia, central statistical agency. Addis Ababa. Statistical bulletin 2019: 589.

Devendra C and Burns M 1983 Goat production in the tropics. Common wealth agricultural bureaux, London, UK; 1983.

Ezekiel A, Abiodun AO, and Oluwafemi O and Adewumi D 2015 Antioxidant activities and nutritional compositions of Vernonia amygdalina. International Journal of Basic and Applied Science. Vol. 04, No. 01, July 2015, pp. 9-16

Fajemisin A and Fadiyimu A 2010 Protein, antinutrients intake and digestibility of west african dwarf ewes fed graded levels of Vernonia amygdalina leaf meal diets. International journal of current research 2010; 2: 57 – 67

Gebremariam T 2005 Mortality and Reported Clinical Signs in Horro Sheep at Smallholder Farms in East Wollega and West Shoa Zones, Ethiopia. Ethiopian. Journal of Animal Production, 2005; 5 (1): 33-42

Gezahegn Mengistu, Getnet A and Samuel T 2020 Noug Seed (Guizotia abyssinica) Cake Substituted with Dried Mulberry (Morus indica) and Vernonia amygdalina Mixed Leaves’ Meal on Growth Performances of Bonga Sheep at Teppi, Ethiopia. Hindawi, Journal of Nutrition and Metabolism 2020; https://doi.org/10.1155/2020/9308761

Girma G, Said A N and Sundstøl F 1994 The effect of forage legume supplementation on digestibility and body weight gain by sheep fed a basal diet of maize stover. Animal Feed Science and Technology 1994; 46: 97-108.

Gizaw S, Abegaz S, Rischkowsky B, Haile A, Mwai A O and Dessie T 2013 Review of sheep research and development projects in Ethiopia. Nairobi, Kenya: International Livestock Research Institute (ILRI); 2013.

Goodchild A V and McMeniman N P 1986 Nutritive value of acacia foliage and pods for animal feeding. In: Turnbull J.W. (ed), Australian Acacias in Developing Countries. Proceedings of an international workshop held at the Forestry Training Centre, Gympie, Queensland, Australia, 4–7 August 1986. ACIAR Proceedings 16.ACIAR (Australian Centre for International Agricultural Research), Canberra, Australia. 1987; 101–106.

Hango A, Mtenga L A, Kifaro G C, Safari J, Mushi E and Muhikambele V R M 2007 A study on growth performance and carcass characteristics of Small East African goats under different feeding regimes. Livestock Research for Rural Development 2007; 19:130; https://lrrd.cipav.org.co/lrrd19/9/hang19130.htm

ILRI (International Livestock Research Institute) 1995 Rumen Ecology Research Planning. Proceedings of a workshop held at ILRI Addis Ababa, Ethiopia 13–18 March 1995

John B G 1994 Evaluation of anthelmintic properties of Ethnovterinary plant preparation used as livestock dewormers by pastoralists and small holder farmers in Kenya. [Doctoral Degree Thesis Dissertation]. Swedish University of Agricultural Science, Uppsala, Sweden; 1994.

Lu C and Potchoiba M 1990 Feed intake and weight gain of growing goats fed diets of various energy and protein levels. Journal of animal science 1990;68: 1751 – 9. https://doi.org/10.2527/1990.6861751x

Matiwos S 2007 Effect of different levels of cottonseed meal supplementation on feed intake, digestibility, live weight change and carcass parameters of Sidama goats. [M.Sc. Thesis Degree] Haramaya University, Ethiopia; 2007

McDonald P,Edwards R A, Greenhalgh J F and Morgan C A 2002 Animal Nutrition. 6^th ed. Prentice Hall, London; 2002

Mekoya A, Oosting S J, Fernandez-Rivera S and Van der Zijpp A J 2008 Multipurpose fodder trees in the Ethiopian highlands: Farmers’ preference and relationship of indigenous knowledge of feed value with laboratory indicators. Agricultural System 2008;96: 184 – 194

Mishra B B, Kidan H G, Kibret K, Assen M and Eshetu B 2004 Soil and land resource inventory at Alemaya university research farm with reference to land evaluation for sustainable agricultural management production. In Kidan H.G and Mishra BB (Eds). Specific feature and management option of soil and land resources of eastern Ethiopia highlands for sustainable agricultural production. Synthesis of working papers, Soil science 2004; Bulletin No 1

Mohammed Ismael 2005 Effects of feeding different levels of Khat (Catha edulis) leftover on feed intake and growth performance of goats fed sorghum stover. [MSc Degree Thesis] Alemaya University, Ethiopia; 2005

Ndlovu L R and Buchanan-Smith J G 1985 Utilization of poor quality roughage by sheep: effects of alfalfa supplementation on ruminal parameters, fibre digestion and rate of passage from the rumen. Canadian Journal of Animal Science 1985;65: 693 – 703.

Negesse T, Rodehutscord M and Pfeffer E 2001 The effect of dietary crude protein level on intake, growth, protein retention and utilization of growing male Saanen kids. Small ruminant research the journal of the International Goat Association 2001;39: 243 – 251. https://doi.org/10.1016/S0921-4488(00)00193-0.

Niderkorn Vincent and Jayanegara Anuraga 2021 Opportunities offered by plant bioactive compounds to improve silage quality, animal health and product quality for sustainable ruminant production: A Review. Agronomy 2021, 11, 86. https://doi.org/10.3390/agronomy11010086

NRC (National Research Council) 2007 Nutrient requirements of small ruminants. National Academy of Sciences, Washington, DC; 2007

Okoli I C, Anunobi M O, Obua B E and Enemuo V 2003 Studies on selected browses of South-eastern Nigeria with particular reference to their proximate and some endogenous anti - nutritional constituents. Livestock Research for Rural Development 2003;15(9). www.lrrd.org/lrrd15/9/okol159.htm

Owen F N and Zinn R 1998 Protein metabolism of ruminant animals. In: The ruminant animal digestive physiology and nutrition. Wavela Inc., Prosepect hights, Illinois, USA; 1988

Powers JJ 1964 Proceeding of 4^th international symposium on food microbiology; Gateborg, Sweden. pp5795

Provenza F D 1995 Role of learning in food preferences of ruminants: Greenhalgh and Reid revisited. In: Von EW, Leonhard-Marek S, Breves G, Giesecke D (eds). Ruminant physiology: digestion, metabolism, growth and reproduction. Proceedings of the 8^th International Symposium on Ruminant Physiology. Ferdinand Enke Verlag, Stuttgart, Germany; 1995.

Salah N, Sauvant D and Archimede H 2014 Nutritional Requirements of Sheep, Goats and Cattle in warm climates. A meta-analysis. Animal 2014; 8(9), 1439-1447

SAS 2011 Statistical Analysis System Version 9.3, SAS Institute Inc., Cary, NC, USA; 2011.

Shapiro B I, Gebru G, Desta S, Negassa A, Nigussie K, Aboset G and Mechal H 2015 Ethiopia livestock master plan. ILRI Project Report. Nairobi, Kenya: International Livestock Research Institute (ILRI); 2015.

Skerman P J and Riveros F 1990 Tropical grasses. FAO plant production and protection series No. 23. FAO (Food and Agricultural Organization), Rome; 1990.

Sukanten I, Lana WK, Suama M, Puger AW and Nitis IM 1992 Effect of gliricidia supplementation on the feeding behavior of Bali local goat. Proceeding of the 6^th AAAP Animal Science. Congr. Bangkok, Thailand. November 23-28, 1992;3:108.

Tadesse Dereje, Urge Mengistu, Animut Getachew and Mekasha Yosef 2016 Growth and carcass characteristics of three Ethiopian indigenous goats fed concentrate at different supplementation levels. Springer Plus 2016; 5:414. https://doi.org/10.1186/s40064-016-2055-2

Van Soest P J and Robertson J B 1985 Analysis of forages and fibrous feeds. Laboratory manual for animal science, Vol. 613, Cornell University, New York, USA; 1985.

Van Soest P J, Robertson J B and Lewis B A 1991 Methods for dietary fiber, neutral detergent fiber and non-starch polysaccharides in relation to animal nutrition. Journal of Dairy Science 1991;74: 3583 – 3597 http://jds.fass.org/cgi/reprint/74/10/3583.pdf

Walie Misganaw, Mekasha Y, Urge M, Abebe G and Goetsch A 2012 Effects of form of leftover khat (Catha edulis) on feed intake, digestion, and growth performance of Hararghe Highland goats. Small Ruminant Research 2012;102: 1 – 6. https://doi.org/10.1016/j.smallrumres.2011.07.014

Wilson R T 1992 Goat meat production and research in Africa and Latin America. In: International Conference on Goats, Pre-conference Proceedings and Invited Papers, volume II, part II, New Delhi. 1992;459-472.

Yoseph Mekasha, Tegegne A and Rodríguez-Martínez H 2007 Effect of supplementation with agro–industrial by-products and khat ( Catha edulis) leftovers on testicular growth and sperm production in Ogaden bucks. Journal of Veterinary Medicine Series A 2007;54: 147-155